Human hair becomes soiled due to its contact with the surrounding atmosphere and, to a greater extent, from sebum secreted by the head. The build-up of sebum causes the hair to have a dirty feel and an unattractive appearance. The soiling of the hair necessitates it being shampooed with frequent regularity.
Shampooing the hair cleans by removing excess soil and sebum. However, the shampooing process has disadvantages in that the hair is left in a wet, tangled, and generally unmanageable state. The latter problem is also prevalent with dry hair. A variety of approaches have been developed to alleviate the after-shampoo problems. These have ranged from the inclusion of hair conditioning aids such as soaps, polymers and cationic agents in shampoos to post-shampoo application of hair conditioners, i.e. hair rinses. Difficulties associated with the use of conditioning aids in shampoos have been compatibility problems and a greasy feels on the just-washed hair.
Hair rinses typically work by depositing a polymeric film or other material onto the hair. However, such solutions to a very prevalent problem have not been fully satisfactory. For one thing, hair rinses are generally liquid in nature and must be applied in a separate step following the shampooing, left on the hair for a length of time, and rinsed with fresh water. This, of course, is time consuming and is not convenient. The results obtained in this manner also have not been fully satisfactory due to the difficulties associated with the deposition and retention on the hair of the hair conditioning aid. The inclusion of suitable conditioning agents in a shampoo therefore has certain attractive features.
As indicated above, many attempts have been made to incorporate conditioning agents into shampoos. One reference disclosing a conditioning shampoo employing a soap in U.S. Pat. No. 3,808,329, Apr. 30, 1974 to Bolich et al. The disclosed shampoos have a pH of 7.0 to 8.4 and contain a polyoxyethylene ester to create a milder shampoo. Another reference is U.S. Pat. No. 3,590, 122, June 29, 1971 to Roberts et al wherein shampoos containing fatty acids which are partially neutralized and having a pH of 5.0 to 8.5 are disclosed. The fatty acids are branched and a preferred acid is isostearic acid.
While the above references disclose using soaps and soaps mixed with unsaponified fatty acids, they are not suggestive of compositions wherein fatty acids are present in a shampoo having a pH of about 3.0 to about 5.5. Furthermore, they do not suggest the advantages of conditioning with a fatty acid rather than soap.
It is an object of the present invention to provide a superior conditioning shampoo composition.
It is a further object of the present invention to provide a superior hair conditioning shampoo composition comprising a saturated, straight chain fatty acid having from about 14 to about 18 carbon atoms, an anionic surfactant and having a pH of from about 3.0 to about 5.5
A still further object of the present invention is to provide a superior method for cleaning and conditioning hair.
These and other objects of the invention will become apparent from the description to follow.
As used herein, all percentages and ratios are by weight unless otherwise indicated.